It's nice that so many countries are signatories, but the countries which are currently involved in significant conflicts, have been, or are likely to be, are all non-signatories, have withdrawn, or are not abiding by their commitment. I'm not sure how much it matters that many non-warring countries are signatories to the convention, unless you think the Ottawa Treaty has actually prevented one or more conflicts (which I doubt).

I find some of the signatories laughable, as both sides in the Russia-Ukraine conflict have used them (with Ukraine being a signatory), while countries like Palestine and Eritrea have committed egregious human rights violations (since assenting), so I don't trust any commitment of theirs.

With respect to chemical and biological weapons, I think the reason they're not widely used is that they're relatively ineffective, and inconvenient, so I don't think they're a force-multiplier at all. Russia & Syria's (likely) uses of chemical weapons seem like more of a (mostly ineffective) desperate gamble than a brilliant move, though they demonstrate the non-existent consequences to such violations of treaty obligations.